As all you fans of "indiana jones" can attest, the biblical relic known as the ark of the covenant has been the obsession of fortune seekers and worshippers alike since days of moses. The holy artifact said to hold the original ten commandments. But there's no consensus as to where it might be or even if it exists. The mystery has inspired a centuries long treasure hunt and christiane amanpour takes us in search of the lost ark. Reporter: Whispers from the past hang in the air of modern day jerusalem. Yet no matter how hard you listen, the truth behind so many of these biblical stories that took place here remain so captivatively elusive. In part, because so many answers may be buried underneath what today is a living, breathing city. This woman is a biblical scholar and a tour guide. She took us to one of the only places where archaeologists, pilgrims and tourists are allowed to explore below this storied city. It's notoriously difficult to dig under the old city of jerusalem. It's very difficult because it's very sensitive. We are talk about holy places of the three main religions. Reporter: It's so politically charged. It is so politically charged. Reporter: Discovered by accident in the 19th century when an archaeologist was walking his dog. This massive network of caves and tunnels is known as solomon's quarries. He is the founding father of the free masons. Reporter: The reminders of solomon, his temple and his destruction seem to seep from these walls. The name of this is theears of the king. Reporter: Why is he crying? Well, this was the end of the first temple period. Reporter: Tears for the destruction of the temple. It was under zedekiah's rule that jerusalem fell to the bab loan yans and the ark of the covenant went missing from history and the pages of the bible. The 10th century is the last time anybody really sees it according to biblical tradition. There are other stories that ybe somebody spirited the ark out of the city just ahead of the destruction. Reporter: Many believe these underground tunnels were used to secretly transport the ark out of jerusalem, and when the bab loan yan troops took infantry of the treasured they blundered, something was missing. When the babalonians took all the inventory, the ark was not on the list. There are all sorts of possibilities as to where it ended up. Reporter: One was that the ark was taken from jerusalem to egypt. That's where indiana jones goes and looks for it. We're told that an egyptian pharaoh may have attacked jerusalem just after the time of solomon. There is one theory that he took away the ark of the covenant. They may have took ark. Reporter: The evidence is underwe underwelming. Back in the caves below jerusalem, we encounter another possibility that as jerusalem fell, the ark was not taken away, but was instead hidden away in this underground labyrinth. Are people trying to be detectives? Are they trying to uncover something? Well, some people prefer to leave it as it is and some people still look and want to find the ark of the covenant. Reporter: Today the idea of the ark transcends time and faith, like so many of the biblical stories, it inspires the simple, yet universal search for meaning. I'm christiane amanpour for "nightline" in jerusalem. You can see much more on "back to the beginning with christiane amanpour" tomorrow night at 9:00 p.M. Here on abc.

This transcript has been automatically generated and may not be 100% accurate.

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